Multilayer ceramic coil and motor using the same

ABSTRACT

Disclosed multilayer ceramic coil ( 4 ) for use in compact motor is configured that ceramic layers ( 4   c ) having a plurality of coil patterns ( 4   a ) and ( 4   b ) printed using a conductive paste are laminated, and that the coil patterns in respective layers are electrically connected via thru-holes ( 4   d ) to form a single multilayer ceramic structure having a plurality of phases of patterned-coil.

TECHNICAL FIELD

The present invention relates to a multilayer ceramic coil and a compact motor (hereafter referred to motor) using the same.

BACKGROUND ART

As shown in FIG. 4, a typical conventional brushless motor comprises a plurality of coils 34 fixed on printed board 36 by soldering and magnet 35 fixed on rotor frame 32, opposing to coil 34 with a gap.

A brushless motor of above configuration has been provided with coils wound by metal wire. Nowadays, however, along with recent advance in printed wired board technology, a different coil manufacturing method is disclosed, e.g., in the Japanese publication of patent application No. S57-68565, No. S57-186940, No. S57-68656 or No. S58-33958 such that to apply a printed pattern of a conductive coil pattern on film 40 composed of epoxy resin, polyester resin and polyimide resin or the like to form coil sheet 44, and laminate a lot of those coil sheets 44 to form a multilayer coil, as shown in FIG. 5.

Such multilayer coil is advantageous to make a compact motor because conventional core wound by metal wire is not necessary and wire winding density is high.

But conventional multilayer coil mentioned above needs an additional process to apply an adhesive layer evenly on a plurality of respective coil sheets 44 for bonding, which results in a problem of production cost increase.

Additionally, the coil sheet composed of plastic or composite materials has a poor thermal proof and are easily affected by ambient temperature. Therefore, operation conditions such as ambient temperature for a brushless motor must be restricted to prevent an unstable movement caused by heat generation due to copper loss and iron loss.

Consequently, a following coil configuration is disclosed to solve the above problems in conventional multilayer coil, in the Japanese publication of patent application No. H5-336712 such that, as shown in FIG. 6, to continue the manufacturing steps of.

-   -   (a) forming a conductive coil pattern on a glass substrate,     -   (b) providing the conductive coil pattern with a glass coating,         and     -   (c) forming a conductive coil pattern further on the glass         coating, and         finally, applying a glass coating on the top surface to produce         a multilayer coil.

Generally, however, the glass used for such multilayer substrate has drawbacks of low impact proof and short life performance.

DISCLOSURE OF INVENTION

A multilayer ceramic coil is disclosed in this invention wherein a plurality of ceramic layers having coil patterns printed with conductive paste and connected the coil patterns of respective layers electrically via thru-holes are laminated to form a single multilayer ceramic structure comprising a plurality of phases of coil.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a motor used in the exemplary embodiment of the present invention.

FIG. 2A is front view of patterns of a multilayer ceramic coil used in the exemplary embodiment of the present invention.

FIG. 2B is a cross-sectional view of a multilayer ceramic coil used in the exemplary embodiment of the present invention.

FIG. 2C is an outline view of a multilayer ceramic coil used in the exemplary embodiment of the present invention.

FIG. 3 is an exploded perspective view of a coil pattern of one phase of the coil pattern used in the first preferred embodiment of the present.

FIG. 4 is a cross-sectional view of a conventional motor.

FIG. 5 is an exploded perspective view of a multilayer ceramic coil of a conventional motor.

FIG. 6 is an exploded perspective view of a multilayer ceramic coil of another conventional motor.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is described by following preferred embodiment with reference to drawings.

Exemplary Embodiment

FIG. 1 shows a motor used in the exemplary embodiment of the present invention. A cross-sectional view of the motor is shown in FIG. 1. As shown in FIG. 1, rotation axis 1 is secured rotor frame 2 vertically. Multilayer ceramic coil 4 is fastened on bearing 3 by means of housing. Bearing 3 holds rotation axis rotatably. Magnet 5 is secured on rotor frame 2 opposing to multilayer ceramic coil 4 with a gap.

Delivering excitation current to multilayer ceramic coil 4, attraction and repulsion of magnet against multilayer ceramic coil 4 produces rotating force of motor.

FIG. 2A shows exploded views of configuration of multilayer ceramic coil 4, FIG. 2B shows a cross-sectional view of the multilayer ceramic coil and FIG. 2C shows an outline view of the multilayer ceramic coil.

Coil patterns 4 a and 4 b printed on ceramic layer 4 c are electrically connected alternately via thru-hole 4 d. Coil patterns 4 a and 4 b of respective phases are electrically connected to crossing pattern 4 e.

In addition, each phase terminal is electrically connected to outlet electrode 4 g by means of terminal pattern 4 f. Outlet electrodes 4 g are mounted at four corners of multilayer ceramic coil 4. Outlet electrodes 4 g are soldered on printed wired board 6 to secure multilayer ceramic coil 4 on the board.

Next, a procedure to form a coil pattern on multilayer ceramic is described in detail with reference to FIG. 3. FIG. 3 is an exploded view of winding formation for a phase of multilayer coil pattern.

-   -   (a) Connect terminal pattern 51 electrically to winding top of         coil pattern 53 a, formed on one layer below, via thru-hole 52         a.     -   (b) Connect winding end of coil pattern 53 a electrically to         winding top of coil pattern 53 b of the formation, formed on         further one layer below, via thru-hole 52 b.     -   (c) Laminate coil patterns 53 a and 53 b from top to bottom to         form patterned-coil 55 a in this way, via thru-holes 52 a and 52         b.     -   (d) Similarly, laminate coil patterns 53 a and 53 b from bottom         to top to form patterned-coil 55 b, via thru-holes 52 a and 52         b.     -   (e) Moreover, connect winding end of coil pattern 53 a on the         bottom layer of patterned-coil 55 a electrically to one end of         crossing pattern 54, formed on further one layer below, via         thru-hole 52 b.     -   (f) Connect another end of crossing pattern 54 electrically to         winding top of coil pattern 53 a, formed on the bottom of         patterned-coil 55 b, via thru-hole 52 a, to provide         patterned-coil 55 a and patterned-coil 55 b with an electrical         connection to an other phase of coil.     -   (g) Finally, connect winding end of coil pattern 53 a on the         uppermost layer of patterned-coil 55 b electrically to terminal         pattern 56 via thru-hole 52 b to provide a patterned-coil having         multiple outlet electrodes.

The multilayer ceramic coil disclosed in the present invention has such a configuration that conductive coil patterns are embedded and laminated in multilayer ceramic structure to provide a coil formation to which excitation current of the motor is fed, which can solve problems in conventional art.

The multilayer ceramic coil has a plurality of ceramic layers having coil patterns printed using conductive paste, connected to the coil patterns of respective layers electrically via thru-holes and laminated to form a single multilayer ceramic structure including a plurality of phases of patterned-coil. In addition, terminals of coil pattern formed inside of the multilayer ceramic structure are electrically connected to outlet electrodes disposed on surrounding surfaces of the multilayer ceramic coil to form terminals for feeding excitation current for motor.

The present invention is not limited to the exemplary example mentioned above but can be used for various application within the concept of this invention.

As mentioned above, the multilayer ceramic coil for use in motor adopts ceramic as an innovative coating material. A motor equipped with the multilayer ceramic coil generates a stable torque force because the multilayer ceramic coil has a higher thermal proof compared with coils provided by plastic, composite materials or glass and has a good heat conductivity. Additionally, the motor shows a reliable performance in various ambient conditions.

INDUSTRIAL APPLICABILITY

The present invention discloses a multilayer ceramic coil and a motor using the same. A multilayer ceramic coil for use in motor is configured with conductive coil patterns embedded and laminated in a multilayer ceramic structure to provide a coil formation to which excitation current for the motor is supplied. 

1-3. (Canceled)
 4. A multilayer ceramic coil consists of a layered plurality of ceramic layers on which patterns are printed by a conductive paste, wherein said multilayer ceramic coil includes: (a) a first ceramic layer on which a plurality of electrically independent coil patterns are printed; (b) a second ceramic board on which a crossing pattern is printed, and said first ceramic layer and said second ceramic board are electrically connected via through-hole to form a single multilayer ceramic structure having a plurality of phases of coils.
 5. The multilayer ceramic coil of claim 4, wherein said first ceramic layer is laminated to a plurality of layers.
 6. The multilayer ceramic coil of claim 4, wherein said second ceramic layer is placed at an end of lamination.
 7. The multilayer ceramic coil of claim 4, wherein said plurality of coil patterns are electrically connected with said crossing pattern, forming an identical number of said plurality of phases of coil.
 8. The multilayer ceramic coil of claim 4 further comprising a third ceramic layer on which a terminal pattern is printed, said third ceramic layer has a common terminal and individual terminals corresponding to an identical number of said plurality of phases and is connected electrically to each of said coil pattern.
 9. The multilayer ceramic coil of claim 8 further comprising a plurality of electrodes which are connected to said terminal pattern respectively.
 10. A motor comprising: a multilayer ceramic coil consisting of a laminated plurality of ceramic layers on which patterns are printed by a conductive paste, wherein sad multilayer ceramic coil includes: (c) first ceramic layer on which a plurality of electrically independent coil patterns are printed, (d) a second ceramic layer on which a crossing pattern is printed, and said first ceramic board and said second ceramic board are electrically connected via through-hole to form a single multilayer ceramic structure having a plurality of phases of coils.
 11. The motor of claim 10, wherein said first ceramic layer is laminated to a plurality of layers.
 12. The motor of claim 10, wherein said second ceramic layer is placed at an end of lamination.
 13. The motor of claim 10, wherein said plurality of coil patterns are electrically connected with said crossing pattern, forming an identical number of said plurality of phases of coil.
 14. The motor of claim 10 further comprising: a third ceramic layerboard on which a connect terminal pattern is printed, said third ceramic layer has a common terminal and individual terminals corresponding to an identical number of said plurality of phases and is connected electrically to each of said coil patterns.
 15. The motor of claim 14 further comprising: a plurality of electrodes which are connected to said terminal pattern respectively. 